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air in fuel lines

Old 01-15-2007, 07:02 PM
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kenny norris
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Default air in fuel lines

new plane new tank new motor new fuel lines lot of air in[:@] lines when half to full throttle help kenny from albany ga.
Old 01-15-2007, 07:17 PM
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Default RE: air in fuel lines

have you balanced your prop?is the tanksurrounded by foam?sounds like yiou have a vibration that is causing fuel foaming,or you have a pin hole leak somewere.you can check for an air leak by emptying the tank and capping all lines execpt the feed line to the engine then apply vacumn to the fuel feed line,I uae an old fuel bulb and watch to see if it fills with air or stays squashed.if no leaks turn up then it is a foaming problem
Old 01-16-2007, 08:59 AM
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Default RE: air in fuel lines

Kenny,
I need a little more informtation.
WHat engine?
WHat Plane?
WHere are you placing the tank?
When you say it "lines" do you mean dies?

ORIGINAL: kenny norris

new plane new tank new motor new fuel lines lot of air in[:@] lines when half to full throttle help kenny from albany ga.
Old 01-16-2007, 09:31 AM
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Default RE: air in fuel lines

I think he's referring to the fuel line or fuel tubing. As mentioned above, is the tank foam padded? Is it soft enough foam that you've used on other planes with success? We had a member with a foaming problem, he replaced the foam with a thicker peice, and his problems were gone.... Greg
Old 01-16-2007, 10:00 AM
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Charlie P.
 
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Default RE: air in fuel lines

The first thing I do when I spot bubbles in the line is to replace the line from tank to carb. 90% of the problems I (and others I have helped) find are caused by a tiny hole on that line. A sharp edge on the metal tube of the tank can put an invisible nick in the line that is enough to suck air and ruin the flow. On a new plane it is often the case that someone pushed the tank up against the firewall or rubbed against something installing it and tore the tubing at that same hard-point. Just the constant vibration and flexing of pulling the line to fill the tank can cause a wear spot at the contact point. 10ΒΆ worth of tubing (that should be replaced occasionally, anyway) saves a lot of aggrivation.
Old 01-16-2007, 10:33 AM
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Default RE: air in fuel lines

If you have a rear mounted needle valve the vibration can be transferred through that needle into the fuel moving through it and the surrounding fuel line and cause the fuel to foam or airrate. I went to the trouble of trying to eliminate it on an OS46FX once and couldn't until i changed the location of the needle valve. I replaced tank, line, foam padded the tank again, replaced clunk, etc but all this wasn't the problem. My problem with this particular engine was the the vibrations of the engine going through the needle valve to the fuel. Now I am not saying all rear mounted needles will do this but mine did and it was only present at very high rpms. Change props to larger one and it went away, change back and the air in the line came back. Change needle valve location and air in line went away and didn't come back with any prop.
Old 01-16-2007, 07:31 PM
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kenny norris
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Default RE: air in fuel lines

kenny again tower hobby75 2 stroke great planes cosmic minnow fuel tank mounted as instructed by manual.i have air in fuel line from tank to rear needle valve and from there to carb when half to full power also got a 12/6 prop on it.i have a great planes little tony with the exact same set up and have no problem. thanks kenny from albany
Old 01-16-2007, 07:37 PM
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Default RE: air in fuel lines

G'day Kenny,
If you have new lines, & you are sure there are no pin holes in the lines, then try balancing your prop, both then blades & the hub, & making sure your tank is isolated from the fuselage, it may be fuel foaming, in the tank.
Old 01-16-2007, 09:50 PM
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Default RE: air in fuel lines

Hey Kenny-
Its nice to see someone else from south west GA on here! Where do you fly? I live in Pelham, and usually fly by myself, but I have been wanting to come up to the Leesburg field to check out that flying club.
It sounds like you might have a pinhole in your fuel line form your tank to your carb- Have you replaced that fuel line? If you have already done that and it didn't help, it might be the pick-up line inside the tank.
Jason
Old 01-17-2007, 06:11 AM
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Default RE: air in fuel lines

If all else fails, spray some Armourall vinyl protectant into your fuel can - one squirt per gallon will eliminate any fuel foaming (try shaking your fuel can - if foam forms, one squirt then try again - voila, no bubbles!)

Cam
Old 01-17-2007, 08:45 AM
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da Rock
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Default RE: air in fuel lines

If the bubbles are coming out of the tank, the problem is in the tank.

It's a new tank. That doesn't mean it hasn't got a leak. The bubbles mean it could have a leak, new tank or not.

Is the stopper tight? Is the screw that tightens the stopper tight? If it is, then loosen it and pull the stopper and inspect to see if the stopper is split or not seating properly.

If your plumbing is for two lines, then most tanks usually have 3 "holes" available. If that unused "hole" has a hole in it..... chuckle.... yeah, not real clear, right...... look at the stopper and look for leaks. Then make sure you have all your fuel lines connected to the correct pipes. If your deliver line is connected to the overflow pipe, etc etc

We always want to do the least work to solve any problem, but with the bubbles in the fuel line problem, the least work usually comes when we simply bite the bullet and pull the sucker and check it completely. It's amazing how many times a new tank has something wrong inside.

BTW, if you're running muffler pressure, then don't worry so much about a leak in the tank. Check for it anyway, but don't get overly excited about finding one. The muffler pressure is actually forcing air into the tank anyway. The bubbles are then either a leak in the pickup line from the clunk somewhere upline, or foaming fuel going into the clunk. Sometimes if the clunk is too close to the backwall of the tank, the suction at the clunk bubbles the fuel when that suction tries to seal the clunk opening to the wall. Or the suction does seal the clunk and holes upline let in air.
Old 01-17-2007, 10:02 AM
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Default RE: air in fuel lines

It sounds like "Fuel Foaming" to me. The vibrations are causing the fuel to turn into foam (It's something fuel does when the conditions are right). Try padding the tank with foam.

I have also heard that a short shot of WD-40 in the fuel will stop it from foaming.
Old 01-17-2007, 07:53 PM
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kenny norris
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Default RE: air in fuel lines

kenny from albany iam in the club in leesburg ga come on up and we will fly. our site is www.geocities.com/clubamac222/ we have realy good guys in our club and be glad to have you come up.let me know ahead of time and i will be there. 229 4365374 kenny from albany.
Old 01-17-2007, 08:22 PM
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sowega flyer
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Default RE: air in fuel lines

Thanks Kenny!
I am looking forward to checking it out! Maybe this weekend- if this crazy weather straightens out!
Jason
Old 01-18-2007, 07:07 PM
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kenny norris
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Default RE: air in fuel lines

jason what kind of plane do yo fly?saturday may be ok weather will know friday always like to check the wind dont like to fly in 15 mph wind just isnt fun. going to try to get the air out of my fuel lines friday if not i do have other planes i can fly but would like to fly my new one kenny from albany
Old 01-18-2007, 07:11 PM
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kenny norris
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Default RE: air in fuel lines

dorock thanks for info on fuel lines its been a pain in the butt for sure kenny from albany
Old 01-18-2007, 07:14 PM
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kenny norris
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Default RE: air in fuel lines

darock had to get your name right kenny from albany
Old 01-18-2007, 07:56 PM
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Default RE: air in fuel lines

I know what you mean about the wind. I fly an Extra 300,but I have a skyraider II that I like to play around with, and I'm installing the servos in a modeltech magic extra 300. That one will be ready to fly this weekend so I'm shooting for sat. for its maiden.
Good luck with your fuel line problem- I know that kind of stuff can get frustrating. I've got plenty of fuel line if you need it.
Jason
Old 01-19-2007, 09:10 AM
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Default RE: air in fuel lines

I use Mr Sheene furniture polish in my fuel. Just a quick squirt and hey! no foaming......But this shouldnt distract you from properly mounting the tank in foam..
Old 01-19-2007, 09:49 AM
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Default RE: air in fuel lines

There are a number of things that people add to their fuel to kill the foaming. Some fuels already contain them. Check the advertising.

One thing we ought to keep in mind when adding something to our fuel, is what might it contain?

WD40 has been mentioned. It's is somewhat similar to fuel or fuel components. And it probably contains nothing that would upset the combustion. And everything in it probably either burns or lubricates. But some things might contain substances that you wouldn't actually want in an engine. Think about what you're adding and what it's probably got in it.
Old 01-19-2007, 07:31 PM
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kenny norris
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Default RE: air in fuel lines

jason i got a skyraider low wing with a 45 super tiger on it good little plane it makes the 3rd one first one hit the ground did not have the radio antenna up the 2nd one wing broke ? dont know if i will be at club sat yet. kenny from albany call me saturday /am /if your comming up 229/4365374.
Old 01-22-2007, 07:13 PM
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kenny norris
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Default RE: air in fuel lines

jason did you get to fly your new plane yet? went to the club sunday but did not fly kenny from albany
Old 01-22-2007, 08:00 PM
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kenny norris
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Default RE: air in fuel lines

kenny got the problem fixed with air in fuel linesthanks for all the info from everybody. so what was the problem? well the motor mount bolts where to long and was hitting the fuel tank inside the fuselage also the stock muffler was up against the fuselage which i though i cleared anyway shorter bolts and a little monkeying around with muffler fixed the problem.i guess the bolts hitting the tank and muffler against fuselage under the tank caused the tank to vibrate anyway no air in lines from idle to full throttle.now its time to blow the wings off a club members little tony which i had a midair and ended up given it to him anway and he says he has got it fixed and is looking for me[>:] thanks kenny from albany.
Old 01-22-2007, 10:20 PM
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Default RE: air in fuel lines

LOL- Glad you got your problem solved Kenny. I haven't flown the magic extra yet- I wanted to fly it last saturday, but my wife told me I had other plans. On sunday I took everything outside to fire the engine up and run it around the ground for testing, but the old starter battery wasn't up to the task, so I'm glad I didn't go all the way to leesburg before I found that out! I'm definately looking forward to good weather this weekend- I can't wait to fly this thing!
Talk to ya later
Jason
Old 01-23-2007, 07:02 PM
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kenny norris
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Default RE: air in fuel lines

jason i will be at club sunday got band practice saturday night and got to carry wife out to eat saturday afternoon i have had a band for the last 7 years we play southen rock country and blues if you and wife would like to come and hear us let me know and i will tell you the next time we play. kenny from albany

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